In 2006, the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA) re-evaluated the toxicology of aluminum. JECFA is an international expert committee that was originally established to evaluate food additives, although its work has since expanded to include such things as contaminants and natural toxins. Health Canada scientists have served as experts during meetings of JECFA and often consider JECFA assessments in their own evaluations conducted as part of Health Canada's regular activities.
As a result of the aluminum re-evaluation, JECFA reduced its Provisional Tolerable Weekly Intake (PTWI) of aluminum from all sources, including food additives. The PTWI is an expression of the amount of a particular substance, in this case aluminum that can be ingested on a weekly basis over a lifetime without increased risk of adverse health effects. The Committee also noted that the PTWI is likely to be "exceeded to a large extent by some population groups, particularly children, who regularly consume foods that include aluminium-containing additives."
In light of the JECFA evaluation, the Bureau of Chemical Safety (BCS) of Health Canada's Food Directorate has initiated a review of aluminum in foods available in Canada. Since aluminum is a naturally-occurring element, it may be found at low background levels in many of the foods we eat. Aluminum may also be present as the result of the use of aluminum-containing food additives, a number of which have a long history of use in food processing. BCS will be working to better quantify Canadian exposure to aluminum, in particular to the various aluminum salts that may be used as food additives in Canada. Bureau Scientists will also be reviewing and updating the regulatory provisions (including the maximum levels of use) for aluminum-containing food additives. To this end, BCS is currently requesting information from the food industry to obtain more details on the use of aluminum-containing food additives (See Health Canada Requests Information from Industry on the Use of Aluminum-Containing Food Additives).
Aluminum is also being reviewed in relation to the Priority Substances Lists of the Canadian Environmental Protection Act, 1999 (CEPA 1999), which identifies substances that may be harmful to the environment or constitute a danger to human health. This review is being undertaken jointly by Health Canada and Environment Canada.
Aluminum is one of the most abundant metallic elements on earth. It can be found in the ground, in water and in air, but not in its metallic form. Rather, aluminum is found in the environment as aluminum compounds, where the aluminum is bound with other chemical species such as silica (for example, aluminum silicate), oxides (for example, aluminum oxide), and hydroxides. Metallic aluminum is obtained industrially from aluminum compounds, the most common being bauxite, a mineral comprised mainly of various aluminum hydroxide compounds. The properties of aluminum and aluminum compounds have led to their use in a wide variety of products such as food additives, drugs (antacids), consumer products (antiperspirants, aluminum foil), and in the treatment of drinking water (coagulation).
Because aluminum compounds are found throughout the environment, aluminum can occur naturally in many of the foods we eat. Aluminum can also migrate into food from cookware, utensils and wrapping materials, but most studies have shown that the amount of aluminum leached from these sources is generally negligible. Certain foods can contain aluminum-containing food additives. For example, sodium aluminum sulphate and potassium aluminum sulphate may be used as pH adjusting agents in baking powder and flour. Sodium aluminum phosphate can be used as an emulsifying agent in certain processed cheeses. Other functions of aluminum-containing food additives include uses in coloring preparations, as firming agents, and as anti-caking agents.
Food additives, including aluminum-containing food additives, can only be used in retail food in Canada if they have been pre-cleared by Health Canada for use in a specific food up to a specified maximum level. For example, sea urchin roe (caviar) may contain potassium aluminum silicate up to a maximum level of 350 parts per million (ppm). Relishes on the other hand may contain this same additive at a level that is governed by Good Manufacturing Practices.
To obtain pre-clearance, a scientific evaluation of the food additive for the intended use must first be conducted by Health Canada. If no concerns are identified during the evaluation, the Canadian Food and Drug Regulations may then be amended to give regulatory approval for the particular use of the food additive. Manufacturers who choose to use permitted food additives in the foods they produce must list each specific food additive along with the other ingredients on the product label.
In the context of food additives, Good Manufacturing Practice or GMP dictates that the minimum amount of the food additive required to achieve the desired technical effect may be used and no more. This principle must always be applied when using permitted food additives. For instance, when the Regulations permit a certain maximum level of use of a food additive, if levels lower than the maximum will achieve the desired effect, then the lowest level should still be used. There are many instances of food additive provisions where the additive may be used at levels consistent with "GMP"; that is, a numerical maximum level is not provided. Some of these GMP listings have been in place for a long time, a few having been "grandfathered" into the Canadian Food and Drug Regulations when the Regulations were first created.
Identifying the maximum level of use of a food additive as "GMP" is an accepted practice for many food additives, such as ascorbic acid, which are of no toxicological concern when used as such. However, Health Canada has a policy of establishing a numerical maximum level of use for those food additives that require more control, such as those containing aluminum. As a result, Health Canada intends to replace any GMP listings for aluminum-containing food additives with numerical maximum levels of use.
Through the on-going Total Diet Study program, Health Canada routinely monitors the levels of aluminum in foods consumed by Canadians. Recent Canadian data suggests that current average aluminum intake through food does not pose an unacceptable health risk to Canadians. However, in light of the recent JECFA evaluation, Health Canada is conducting a more detailed assessment of dietary exposure to aluminum in order to provide more insight into the range of exposures among Canadians. The results of this assessment will be used to identify whether further controls on aluminum in food in Canada are required.
Most studies show that very little aluminum is actually absorbed by the body from the gastrointestinal tract. Absorption of aluminum can depend on a number of factors such as the composition of the food eaten, the type of aluminum compound and the age and health of the person. Historically, aluminum has been considered relatively non-toxic. However, an abundance of scientific studies are now showing that long-term exposure to elevated levels of aluminum may adversely affect humans and animals.
For example, studies conducted in some species of experimental animals suggest that various aluminum compounds, when added to the diet or to drinking water at high enough levels, are capable of causing adverse effects related to reproduction, neurological behaviour and neurological development. Aluminum is often suggested as a possible cause of Alzheimer's disease; although, to date research results that suggest an association between high aluminum accumulation in the body and Alzheimer's disease are not considered conclusive.
The Bureau of Chemical Safety in Health Canada's Food Directorate has initiated a review of dietary exposure to aluminum in Canadian foods to identify whether further controls on aluminum in food in Canada are required. While current average estimates of dietary exposure to aluminum among Canadians do not indicate that there is an unacceptable risk, Bureau scientists are more closely examining dietary exposure using more sophisticated modelling techniques to ensure that there are no segments of the Canadian population that are being exposed to unacceptable levels of aluminum. BCS scientists are also reviewing the current uses of aluminum-containing food additives in Canada with the intent of replacing maximum levels of use that are shown as "GMP" with numerical maximum values.
More generally, Health Canada collaborates with the Canadian Food Inspection Agency to ensure that appropriate action is taken when any chemical is found in food at levels that are considered to pose an unacceptable health risk. Health Canada has an ongoing program tasked with evaluating the latest scientific data on chemicals in food, assessing any associated health risks, and identifying appropriate means of reducing these risks.
Health Canada is also a key contributor to the Canadian Environmental Protection Act (CEPA, 1999) assessment of aluminum. Aluminum and aluminum compounds are currently undergoing a thorough review process under CEPA in order to gauge the current impact of aluminum on the environment and the health of Canadians.